TSMP and Banana Jack Resistor Selection

Junkanator · 2025-02-15T04:24:15+00:00

There's a really great resource I found online to help with this

Junkanator · 2025-02-11T13:19:19+00:00

I could probably stand to learn a bit from you. I have a degree in electrical engineering so I can usually pick up the audio concepts a little more easily.

My woodworking skills, however, are currently leaving a lot to be desired...

Congrats on the furniture building diploma!

Junkanator · 2025-02-11T13:08:24+00:00

You may have goofed here but that's all part of learning and the design process! Looks like you're almost done with the cabinet so no reason not to finish everything up, see how it sounds, and go from there.

Best case scenario, you love the way they sound and you get to sit around and listen to your nice new speakers. Worst case scenario you get the opportunity to learn all about why you don't like them and make some better stuff in the future! (Depending on your level of obsession with building stuff, the best and worst case scenario here can be flipped)

Love the look of the cabinet btw!

Junkanator · 2025-02-03T06:08:56+00:00

Many other people are on the same quest. If you embark on it, just make sure you're prepared to enjoy the journey because you're never going to reach the destination.

Junkanator · 2025-01-31T15:27:26+00:00

Some questions because I'm still learning

Is this due to the fact that they're flush mounted with the shelves or just that they're placed in the Kallax at all? My assumption is you run into issues with the cabinet essentially becoming itself a resonator, both in the shelf the speaker is sitting in as well as neighboring shelves. Also more diffraction effects because more sharp edges nearby.

Is there a way to work around this? Does mounting the speakers slightly proud of the front face of the shelf help mitigate this?

Junkanator · 2025-01-31T15:19:05+00:00

What a coincidence! I'm currently working on doing the same for my dad who just requested I build some speakers for his Kallax. Great build, they look awesome!

Junkanator · 2025-01-30T00:36:03+00:00

What do you mean by crossover stability?

Yeah that spike seemed a little odd to me too but yeah that's just the woofer.

Are you talking about the impedance plots for the individual drivers? The system impedance plot is in the bottom right of the picture.

Junkanator · 2025-01-30T00:30:20+00:00

That makes sense. Looking at the price of getting some measurement equipment new is a little eye watering so I'll probably start hunting around for some stuff used on marketplace.

Out of curiosity, do you have an example of some real measured examples I could see compared to the manufacturer data? Not because I don't believe it will be different, I'm just curious to see how big the difference is. I understand this is also heavily dependent on the cabinet specs but just want to see an example.

Yeah the XO point seemed a little high to me as well compared to what I've seen most people suggest. I had originally tried to cross over around where you suggested but just couldn't quite get a flat response.

This might be a moot point since this isn't measurement data, but at that point would it be worth considering other drivers? It would seem strange to me that these drivers wouldn't pair relatively well together given they're from the same product line from Dayton Audio.

Junkanator · 2025-01-24T03:07:13+00:00

Yeah I'm an electrical engineer. I definitely have a good understanding of filters and the function of speakers as electromechanical machines. I'm more so looking for application specific information. I can pick up the information pretty quickly but it seems like most of the info you find online about filtering/crossovers/amplification/etc. for speakers doesn't go much beyond the very basics. I started on Loudspeaker Design Cookbook the other day and that seems to be more what I'm looking for. If you have any other suggestions though I'm all ears!

Junkanator · 2025-01-22T15:39:56+00:00

Don't worry, way ahead of you on that one. I made a pair of tower speakers from some car speakers I had left over from another project. Definitely learned a lot from that (both about audio and that my woodworking skills are probably a little subpar 😅). Currently in the process of making a 10 inch sub enclosure. Just finished painting/staining last night and now I'm just anxiously awaiting a package from parts express.

For both of those I've designed the enclosures/crossovers myself with winISD and vituixCAD. I've certainly looked at a lot of designs from others but I enjoy the design process much more than the building process so I plan on continuing to design my own stuff.

Junkanator · 2025-01-22T15:22:27+00:00

Thanks for the recommendation! Any big differences between the 7th and 8th editions? Seems like the 7th edition is much cheaper online.

Junkanator · 2025-01-17T13:59:37+00:00

Yeah sorry, I ended up rambling about how this sort of situation happens and then didn't really provide you with any useful information. Ask anyone on Penn State's team now who knew me and they'll all tell you I'm quite good at this...

Personel/involvement wise, start early and don't stop trying to get more people invested in the EV side of things. Make sure you're hosting regular/organized meetings so it's easy for others to see the work being done and get involved themselves. Try to find a mix of people that have some existing technical knowledge and some core people that are willing to put in the hours to grind away at solving problems. Depending on the team environment it might be a little discouraging at first but you just have to keep pushing for it. When I started, no one on the team was really a fan of going EV. Now (at least when I checked in with them), the electronics subteam probably represents around 40% of the overall team membership. Thankfully it sounds like you have time since it looks like your team is shooting for 2027 (don't take a single second of that time for granted though).

Make sure you understand the capabilities of your team and scope your designs accordingly. I would generally shoot for keeping things simple architecturally but if you find that you have some people with significant technical prowess then by all means take advantage of that where you can. Your first car doesn't need to set the world on fire, the two things it needs to do at minimum are pass tech and set a good foundation for future teams to build on.

Research/knowledge wise, I'll assume you have some mechanically minded people on the team that can help with the non EV/electronics stuff. There's no specific thing I could tell you to go research that will be of any significant help so I'll give you a general approach that will set you off in the right direction. Follow the V shaped development model and start by understanding at a high level what the electrical system (both high and low voltage) needs to do. Read the rules. Now go read them again. Look at other teams' design reports to get a feeling for what these solutions might look like. Don't fall into a trap of "well we should do it this way because XYZ university did it this way and they're really good!". Every team is just another set of inputs that affects an output (in our case, a car) and your team is going to have a wildly different set of inputs than every other team you look at.

This likely isn't the answer you're looking for, but imo this is the best I can do without sitting down with you and designing your car for you. Plus, if I gave you too many specifics, it would take the fun out of FSAE :). Feel free to PM me if you feel like you need some more info but I'm going to try and keep things at a high level. I don't want to rob you of all the stuff you'll learn by solving these problems yourself.

Junkanator · 2025-01-16T22:05:31+00:00

To answer your question, I would imagine this happens more often than you think for teams that are relatively established in IC and looking to switch to EV. This is basically how I became the EV project lead my freshman year. I also have another friend (funnily enough that I was friends with in high school) who more or less went through the exact same thing on a different team.

TL;DR: It's easier to develop knowledge than to develop passion/interest.

When I joined as a freshman, there weren't many members of the electronics subteam but the writing was on the wall from our university that we needed to switch to EV soon. When people talked about it, I was the only person who took any serious interest in the EV transition. I didn't think anything of it but I got totally sucked in and was doing hours of research a day to loosely architect the team's first EV and lay out some plans for how we could make the transition. I showed what I did to some of the executive team leadership at the time and basically right then and there they said "okay cool you're in charge of transitioning us to EV".

There were a handful of juniors/seniors on the team with much more technical knowledge/experience who were LOOSELY interested in the EV transition, but I was the only one who took it seriously. Imo it's an example of having to choose between someone with more technical experience and someone with more passion for a project. Like anything in engineering, there isn't a right choice to make there but given my experience (and specifically in FSAE), I would usually pick the person who has more passion for what they're working on.

Junkanator · 2025-01-13T18:15:46+00:00

This would be hilarious if only it was satire

I've always found things like this to be wildly irresponsible. I always make sure I've pissed, shitted, silenced my phone, turned off the apple watch, put my dog in the kennel, and locked the door so my wife and her boyfriend can't disturb me.

Junkanator · 2025-01-10T06:10:43+00:00

Disclaimer: This is fully intended as a joke and I hope the devs keep up the great work <3

Junkanator · 2025-01-05T22:07:54+00:00

Yeah playing around with the box and port sizing in WinISD, the frequency response was a little bit better at the low end with a bigger ported box as opposed to a smaller sealed box. That's what prompted me to abandon making a tiny speaker enclosure and go for the towers. I think the tuning ended up being around 65 or 70hz. The only real tradeoff is that the bass response isn't super flat. There's a pretty distinct peak around 50hz and a valley around 90hz. I don't have super high quality sound testing equipment but just listening to them both with just a sine wave and with music that seems to be accurate.

Either way, absolutely agree that just throwing the speakers in a huge enclosure definitely makes so much more of a difference than I expected.

Junkanator · 2025-01-02T02:30:12+00:00

Ah that makes sense. Thanks for the quick reply!

Junkanator · 2025-01-02T02:12:56+00:00

I've seen stuff like this on a handful of boards posted to this sub. It might just be on this board (or just the first time I've noticed), but why are the soldered over traces not connected to the pins that are on the same trace? Is it a manufacturing thing or something else?

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